Managers-Net

Analytical Estimating

What is it ?

Analytical estimating is a structured work measurement technique. The formal BSI definition (22022)
states that it is a development of estimating, in
which the time required to perform each constituent part of a task at
a defined rate of working is estimated from knowledge and practical
experience of the work and/or from synthetic data

An important feature of this
technique, which helps to improve accuracy, is that a whole job
should be broken down into smaller individual tasks. This is because
any errors in the time estimates may be seen as random and will
therefore compensate for each other.

How can it be used ?

Analytical estimating would
normally be used for assessing work over a reasonably lengthy period
of time, where it may be difficult and more expensive to collect the
information required using other measurement techniques. Also, in
some work environments the presence of an individual carrying out
work measurement in the work place could be unacceptable. In these
cases, analytical estimating may be an appropriate method to use,
assuming someone with experience of the work is available to apply
their experienced judgement. ( This may be work measurement personnel
who have previous experience of this particular work )

However, the work content of some
jobs cannot be estimated in advance because one is unclear about what
is required until an assembly operation has been tested or stripped
down. For example, during the progress of repair unforeseen and non
standard difficulties can arise. Removing a wooden door from its
frame by unscrewing 8 or 12 screws could take five minutes if the
screws were recently inserted, or a great deal longer if the screws
are rusted and clogged with paint.

In summary, the technique is used
most commonly in any work environment where a lengthy time (and
associated high cost) is needed to collect data.

Advantages & Disadvantages

Perhaps the most significant
advantage of using anaytical estimating is its speed of application
and low cost. Using trained and experienced personnel process and
measurement data can be quickly assembled and applied.

However,
the use of experienced judgement when determining the time necessary
to perform a task is the technique's most obvious source of weakness
when compared with a more precise technique such as
time study.
This is why the technique would not normally be used when a more
precise and accurate alternative is a feasible and economic
alternative, particularly to highly repetitive, standardised
operations. Many jobs, such as craft work in the maintenance field,
consist of a group of tasks which are periodically repeated but the
precise nature of each task varies each time in minor respects (
see research on Natural & Normal Variation for further
explanation). In this example, since it is impractical, in terms of
time and cost, to allocate one time study observer permanently to
each craftsman, the alternative is to use a time-study basis plus
the experienced judgement of an ex-craft work-study observer to allow
for detailed task variations.